Carburetor



y 1932- P. E. MIQUELON 1,860,869

CARBURETOR Filed July 5, 1928 a y 12 v a! I fiufenTor Fan/Qwz [/Ziae/mzPatented May 31, 1932 UNITED STATES PATENT OFFICE Application filed July5, 1928. Serial No. 290,476.

This invention relates to improvements in carburetors and it consists ofthe matters hereinafter described and more particularly pointed out inthe appended claims.

he primary object of the invention is to provide a carburetor forinternal combustion engines which permits of an easier starting andwarming up of the engine, gives a better idling andlow speed performancethereof and greater when required.

Another object of the invention is to provide a carburetor which iseconomical in fuel consumption and is of such a simple construction asto make it easy and practical to manufacture, the parts being so madeand correlated that the carburetor cannot readily get out of order.

These objects of the inventlon as well as others, together with the manyadvantages thereof will more fully appear as I proceed with thespecification.

In the drawings Fig. 1 is a diagrammatic longitudinal Vertical sectionalview through a carburetor embodying my invention, with the parts 1n theposition they occupy for starting and warming up the associated engine.

Fig. 2 is a similar view with the parts in the position they occupy whenthe engine is idling and the metering pin is free from the dash control.I v

Fig. 3 is another similar view with the parts in the position theyoccupy as when the throttle is wide open and the metering pin iscontrolled by suction.

Referring now in detail, to that embodiment of the invention illustratedin the accomnanying drawings:1 indicates as a whole the shell of acarburetor of the plain tube type, having the usual float bowl andmechanism 2 for controlling the flow of liquid fuel thereinto from afuel supply pipe 3.

' The float bowl mechanism maintains the liquid lex'el in the carburetoras is indicated by the dotted line 4. In the shell 1 near its top end islocated a throttle valve 5 mounted on a shaft 6 that projects throughone side of the shell and there has power output and flexibility--.Iport 17 with end of the said cylinder.

attached to it, a lever arm 7 by which the throttle may be opened andclosed.

Between the shell and float chamber is provided an upright cylinder 8which is connected at its bottom end by a port 9 with the fuel bowl andin said cylinder above said port is an air measuring cone 10 with apassageway 11 therein. This passageway tapers downwardly as shown.Between the bottom of said cone and the port 9 there is provided in saidcylinder, a valve seat or liquid fuel metering orifice 12.

' In the shell 1, substantially midway between its ends is a Venturitube 13 and a horizontally disposed conduit 14 opens through said tubeinto the cylinder 8 near its to end. 15 indicates the main fuel nozzle.vaid nozzle is herein shown as substantially L-shaped and its horizontalleg opens through the cone 10 and its vertical leg which is disposedcoaxially with respect to the Venturi tube 13 terminates a shortdistance above the bottom thereof. 16 indicates a fuel by-pass tubewhich is connected at its bottom end with the cylinder 8 between thecone 10 and orifice 12 and consequently below the fuel nozzles and isconnected-at its top end with the shell 1 so as to open thereinto abovethe throttle 5. The cylinder 8 is connected at one side above the cone10 by a ;the""air-int ake end of the shell below the Venturi tube and isopen at its other side to atmosphere by a port 18.

Arranged in the cylinder 8 is what I term a combined liquid fuel andair'metering pin 19, the top end of which has an enlarged head 20disposed above and without the top The bottom end of said pin which istapered, extends down through the orifice 12 and its normal positionwith respect thereto may be determined by means of an adjustment screw21 threaded into the bottom end of the cylinder 8. -On said pin, shortlyend thereof so s to coact with the tapered bore 11 of the measuring cone10, is a collar. 22 and also fixed to said pin normally above. the ports17 and 18 is a piston 23 which snugly fits the bore of said cylinder. Aspring 24 surrounds said pin between the top end of above the taperedbottom forms a part.

said cylinder and said piston and normally acts to urge said piston andpin downwardly.

Means is provided by which the metering pin may be manually lifted orraised, from the dash of the automobile in which the engine equippedwith my improved carburetor Said means includes a bell crank lever 25which is pivoted to a bracket 26 on the .top end of the cylinder and'onearm of said bell crank is engaged under the metering pin head 20 whilethe other arm has connected to it a link or wire 27 .leading to the dashin a position convenient for the operator.

Pivoted between its/ends to the cylinder 8 just above the port 18 is alever 28 with one of its arms disposed within the cylinder so as to beengaged under certain conditions with the underside of the piston23'therein, while the other end of said lever carries a ball 29 throughwhich slides the bottom end of a link 30. The top end of said link ispivotally connected to the throttle arm 7 and a spring 31 surrounds saidlink to engage at one end with the ball 29 and at its other a shoulder32 on said link.

end against above de- The operation of the carburetor scribed is asfollows: I

Assume that the engine is at rest and is cold and it is desired to startand warm it up.

The throttle will be closed and in this rest period of the engine, fuelbuilds up in the V nozzle 15, the cone bore 11 and the by-pass 16 andwill assist in enriching the mixture for starting. The operator shouldthen manipulate the dash link or wire and this will, by reason of thebell crank lever 25, lift the metering pin 19 which in effect willincrease the size of the fuel 12 as best shown in Fig. 3. As the engineturns over under the action of the starting motor, a suction action isproduced in the shell above the throttle 5 which is still closed, sothat by this time the bypass 16 becomes in effect a solid column of fueldischarging into the engine manifold to give the rich mixture necessaryfor starting. With the engine turning over under its own power,

; volume of the mixture the dash link or wire is released and the partstend 'to return to their normal posi tion and the throttle .5 is nextopened.

Through the link 30 the lever 28 is rocked so that the inner end of saidlever will slightly lift the piston 23 thus holding the metering inraised and an increased flow of air is afiorded through the bore 11 andan increased flow of fuel through the orifice 12. Thus the through theby-pass 16 into the neck of the shell 1 above the throttle 5 may bevaried by the manual setting of the metering pin without regard to theposition of the throttle. By this arrangement an increase in the idlingspeed of theengine during the warming up period maybe had withoutdisturbing the setting metering aperture 12 proportionate to of thethrottle for idling when the engine is warm and the stalling of theengine during the warming up is prevented.

1Vhen the engine is idling, engine suction is exerted upon the by-pass16 to the fuel orifice 12 and bore 11, air therefor being suppliedthrough the ports 17 and 18. The amount of air in this instance iscontrolled or measured by reason of the collar 22 on the metering pindue to its position in said bore 11 and this modifies the suction actionat the operation of the encrease in the flow of fuel in proportion tothe increase of air flow past the throttle valve 5-. This amount ofincrease of fuel for any given amount of lift on the metering pin isdetermined by the taper of the bottom end of the metering pin and bore11, both of which is ascertained in the shop. In this raising of themeter pin, assistance is provided by the atmospheric pressure exerted onthe bottom end of the piston 23 which is further influenced by thesuction action on the top of said piston through the port 14 whichconnects the cylinder 8 with the interior of carburetor shell at theVenturi tube and the amount of this suction, of course, varies withengine speed.

When the throttle 5 has reached a predetermined open position as forinstance, about two thirds of wide open position, the collar 22 on themetering pin has reached a point slightly above the inlet end of thefuel nozzle 15. At this throttle opening with its corresponding motorspeed the suction increases at tube 13 so that it is greater than thatabove the throttle in the vicinity of the by-pass 16 and in consequenceno fuel is fed through the by-pass 16', but only through the nozzle 15which delivers it axially into the air-stream passing through therestricted end of the Venturi tube.

At this time should the throttle be closed down a bit so as to moderatethe engine speed, the reverse operation of the arts above mentionedtakesplace.

With the throttle valve in the wide open position shown in Fig.3,1'engine suction in the cylinder 8 above the piston 23 through theport 14, issufficient to control the position of the metering pin 19 sothat it will permit the passage of fuel through the orifice the amountof air entering the restricted part of the Venturi tube 13,

but slightly opened through the the restricted part of the Venturisition to said suction.

- period and up to without any mechanical aid except that of the spring24 acting on the piston 23 in oppo- The tension of said spring. which ispredetermined, is such as to insure the proper position of the meteringpin 19 for different engine loads and corresponding suctionsQ In thisoperating position, engine suction is greater at the venturi than it isin the shell 1 where the by-pass 16 discharges thereinto so that allfuel for the engine when the engine is running with a wide open throttleis supplied by the nozzle 15 The construction described has manyadvantages in that all ranges of engine speeds, from cold startmgthrough the warming wide open throttle is effectively taken care of.Starting a cold engine is made easier and the danger of choking andconsequent period is eliminated and consumption.

N 0 liquid fuel is lifted by suction above the normal liquid levelexcept through the bypass when starting as before explained and thepositive delivery of fuel at the highest suction even with smallthrottle openings is made possible and positive by the automaticallyvaried discharge of the bypass 16 above the throttle valve.

.The Venturi tube 13 has no effect on low speed performance of theengine and consequently the restriction thereof is only determined bythe maximum output of the engine and as there is no compromise betweenthese two speeds, the size of the said restricstopping during warming upthis with a low fuel tion can be indeed accurately determined. Again, asthe control of the metering pin is 1n accordance with engine suctionafter starting, the proportionate amount of fuel for correct mixturesfor matically made.

Again it is pointed out that the metering orifice is disposed not onlybelow the level of fuel but also below the inlet for the main nozzle andthis together with the associated elements permits the fuel flow to beinfluenced both by suction and gravity. Thus, less energy is required tolift the liquid fuel into the air stream and liquid fuel will be pickedup or aspirated at the nozzle 15 at slower engine speeds or with alarger size of venturi and this results in a greater power range.

By the manual lifting of the metering pin through the dash link or wire,the by-pass is momentarily transformed into a solid fuel jet on thesuction side of the throttle so that all engine speeds is autothe latteris effective as a choke in starting.

' her and a main referred in detail to the several parts, to-

gether with their relative locations, the same must be considered asillustrative only so that I do not wish to be limited thereto except asmay be pointed out in the appended claims.

I claim as my invention 1. In a carburetor, the combination of a mixingchamber having a main air-inlet and a discharge outlet, a throttle valvefor controlling said outlet, a fuel nozzle for said mixing chamber,means for supplying fuel to said nozzle, a by-pass communicating withthe discharge of said mixing chamber above said throttle valve, meansfor supplying air and fuel to said bypass, and a valve for controllingthe amount of air and fuel supplied to said by-pass, a piston on saidvalve, a cylinder for said piston, yielding means for moving said pistonand valve in a direction to decrease the amount of fuel and air suppliedto said by-pass, and a conduit providing communication between-saidcylinder and said mixing chamber for moving said piston and valve in adirection to increase the amount of fuel and air supplied to saidby-pass in proportion to the amount of suc-. tion in said mixingchamber.

2. In a carburetor having a mixing chamber and a main air inlet, adischarge outlet and a throttle valve for said discharge outlet, meansproviding a' supply of fuel for said carburetor, a metering orifice forsaid fuel, means for providing an auxiliary supply of 'air to mix withthe fuel before it is discharged into said mixing chamber, a meteringorifice for said auxiliary air supply, a metering pin extending throughboth of said orifices and having a tapered end disposed in said fuelmetering orifice and an enlargement thereon, the said air meteringorifice having tapered walls leading thereto, the enlargement of saidpin cooperating with said tapered walls to vary the amount of airpassing therethrough upon movement of said pin, and manual means formoving said pin to open the orifice when the suction in said mixingchamber is lowest.

3. In a carburetor having a mixing chamair inlet, a discharge outlet.and a throttle valve for said discharge outlet, means providing a supplyof fuel for said carburetor, a metering orifice for said fuel, means forproviding an. auxiliary supply of air to mix with the fuel before itdischarges into the mixing chamber, a tapered metering orifice for saidauxiliary air supply, a metering pin extending through both of saidorifices and having a tapered end disposed in said fuel metering or ficeand an enlargement thereon, the said air metering orifice having taperedwalls leading thereto, the enlargement of said p1n cooperating with saidtapered walls to vary the amount of air passing therethrough uponmovement of said pin, a piston on said metering pin, a cylinder for saidpiston, yielding means for moving said piston and pin in a direction todecrease the amount of fuel and air passing through said meteringorifice, and a conduit providing communication between said cylinder andsaid mixing chamber for moving said piston and pin in a direction toincrease the amount of fuel and air passing through said orifice inproportion to the amount of suction in said mixing cham her.

4:. In a carburetor, the combination of a mixing chamber having a mainair inlet and a discharge outlet, a throttle valve for controlling saidoutlet, a passageway having a fuel supply communicatin therewith at oneend thereof, an air supp y communicating therewith at the other endthereof, a nozzle for said mixing chamber communicating with saidpassageway intermediate said air and fuel supplies, a fuel by-passhavingone end communicating with the discharge of said mixing chamberabove said throttle valve and the other end thereof with said passagewayin spaced relation to said nozzle connection, an element movable in saidpassageway for varying the amounts and proportions of air and fuelsupplied to said nozzle and by-pass, manually operable means for movingsaid element, and automatic means controlled by suction 1n said mixingchamber for continuing the movement of said element.

5. In a carburetor, the combination of a mixing chamber having a mainair inlet and a discharge outlet, a throttle valve for controlling saidoutlet, a passageway having a fuel supply communicating therewith at oneend thereof, an air supply communicating therewith at one end thereof, anozzle for said mixing chamber communlcating with said passagewayintermediate said air and fuel supplies, a fuel by-pass having one endcommunicating with the discharge of said mixing chamber above saidthrottle valve and the other end thereof with said passageway in spacedrelation to said nozzle connection, an element movable in said pas'sageway for varying the amounts and proportions of air and fuel suppliedto said nozzle and by-pass," means operated by 'xnovement of saidthrottle valve for imparting limited movement to said element, andautomatic means controlled by suction in said mixing chamber forcontinuing the movement of said element.

In testimony whereof, l have hereunto set my hand, this 26th day ofJune, 1928.

PANT LEON E. MIQUELON.

